I've been spending the last few weeks convincing myself that I love my E-M10 and I would not want/need to upgrade to the E-M5II... However...for reason's I'll not get into (mainly because it will mean admitting that I'm a weak, impulsive, whimsical fool)...When I arrive home from work this evening, I'll have a box waiting for me that contains an E-M5II along with a 75/1.8 (I really went to Adorama's site to buy the lens...honest!) So...as I said I really am happy with my E-M10. It is small, fast, light and has awesome image quality. I find since switching to this m43 kit I take my camera with much more, where when I was shooting a bulky SLR system I'd only take it with if I really felt the need. Now I just like the camera so much I find myself finding more reasons to go out and shoot. I know if I go home and open that box, I'll gain a better IBIS system, weather sealing, slightly higher FPS, and 1/8000 shutter speed vs. 1/4000. I'm not sure how much I'd need to shoot faster than 1/4000. 8FPS on the M10 already feels like a machine gun and I just don't feel I'd need anything faster. Better IBIS and weather sealing, yeah I definitely see the benefits there. On the flip side...the E-M10 of course has a popup flash...but to be honest I'm an available light kind of shooter and on the occasions I do use flash...it's generally bounced which requires a flash unit anyway. I believe both cameras are roughly the same size, give or take a few mm here or there. So, if I should decide to go home and open the box...what else would I really be gaining over the E-M10?